Shear pin drive for gyratory crushers



L. R. FERGUSON SHEAR PIN DRIVE ox GYRATORY CRUSHERS Filed July 23. 1959INVENTOR Lester R. Ferguson 0 BY m zauwamfi x ATTORNEYS 3,000,577 SI-EARPIN DRIVE FOR GYRATORY CRUSHERS Lester R. Ferguson, Riveredge, N.J.,assignor to Kennedy Van Saun Mfg. & Eng. Corporation, New York, N.Y., acorporation of Delaware Filed July 23, 1959, Ser. No. 829,047 Claims.(Cl. 241--32) My invention relates to improvements in gyratory crusherconstructions and more particularly to a driving connection directlyassociated with the eccentric of the crusher and including a safetyarrangement provided with shear bolts for avoiding damage to thecrusher.

In general, gyratory crushers are very heavy and expensive machines inwhich a main shaft is oscillated by an eccentric to in turn oscillate amantle carried by the shaft within a grinding or crushing ring. Suchcrushers are likely to be damaged very severely if pieces of tramp ironcontained in the rock being crushed come between the mantle and grindingring. Such pieces of tramp iron cause very serious damage where they areso large that they cannot pass between the crushing members even underthe give of the springs supporting the main shaft and mantle of thecrusher.

Crushers of the type under consideration are particularly the gearlesstype crushers in which the eccentric is driven by a directly mountedelectric motor or by a belt-flywheel drive. These and other parts of theusual driving means are so large in diameter, so heavy, and consequentlyhave such a momentum when in operation that a piece of tramp ironbetween the grinding elements is bound to and has caused serious damageto the crusher. In such cases the loss is not only for the broken partsof the driving and other equipment but also for the time and expenseinvolved in taking down the crusher and repairing it.

Therefore, the primary object of my invention is to provide a safetystructure arrangement in the driving connection to the eccentric whichwill protect the crusher against damage when some uncrushable object,such as a piece of tramp iron, enters the space between the crushingelements.

A further object of my invention is to provide a safety constructionwhich is easy to install in existing gyratory crushers and easy toinclude in new crusher constructions.

Another object of my invention is to provide a safety construction ofthe type referred to, which is readily replaceable when the movement ofthe crusher mantle is stopped by an uncrushable object between themantle and grinding ring of the crusher.

-In accordance with my invention the driving connection to the eccentricof a gyratory crusher is provided with a driving dog structure,including shear bolts which are normally adapted to take the drivingforce for the eccentric but which are adapted to be sheared off whenmovement of the eccentric is stopped or retarded abnormally, as forexample abruptly by the presence of tramp iron or some otheruncrushab'le object between the crushing elements of the crusher.

In a particular construction the coupling mechanism or driving couplingbetween the usual driving disc, driven by a drive pulley or motorattached thereto, includes a driving dog structure keyed to theeccentric and provided with dogs attached to the driving dog structurewith shear bolts located in a position to be sheared off when theeccentric encounters unusual resistance, as explained above.

The invention is described more in detail hereinafter in connection Withthe accompanying drawings illustrating one structural embodiment of theinvention.

Patented Sept. 19, 1961 ice In the drawings:

FIG. 1 is a broken view partly in vertical section of the lower portionof a gyratory crusher, in which the invention is illustrated;

FIG. 2 is a horizontal sectional view taken through the driving dogstructure on the line 2-2 of FIG. 1; and

FIG. 3 is a broken vertical sectional view taken on the line 3-3 of FIG.1.

The drawings show only the lower portion of the gyratory crusher towhich the features of the present invention are concerned, it beingunderstood that the gyratory crusher includes a main driving shaftcarryung a mantle operating within a concave or grinding ring foreffecting the crushing of stone of various kinds. In gyratory crushersof this type the main shaft is suspended on springs or other suitableresilient means, so that the mantle has some give vertically during thecrushing operation.

The lower portion of the crusher shown in the drawings includes astationary depending cylindrical annular sleeve member 10 normallycomprising an integral part of a bottom plate bolted to the bottom shellof the crusher. The depending sleeve 10 comprises a stationary part ofthe crusher, and its inner cylindrical surface is lined with a bearing12, within which an eccentric 14 is rotatably mounted. The eccentric asin known structures includes an inner cylindrical cavity 16 which is offcenter with respect to the outer cylindrical surface, illustrated inFIG. 1 by showing the wall at the right substantially thicker than thewall at the left.

The main shaft of the gyratory crusher shown at 18 extends, in the usualmanner, into cavity 16 of the eccentric 14 and is provided with a sleeve20 lined with a bearing material 22 fitting the cylindrical outersurface of the main shaft 18. The sleeve 20 comprises a part of a knowntype ball and socket bearing structure located in the cavity 16 of theeccentric and not shown in the drawings. The ball and socket bearingstructure associated with the sleeve 20 and eccentric 14 is off centerwith respect to the outer surface of the eccentric 14, so that therotation of the eccentric 14 within the sleeve 10 causes the shaft 18 tooscillate and effect the crushing and grinding, in the usual manner.

The gyratory crusher illustrated in FIG. 1 is of the gearless typehaving a driving pulley 24 provided with the usual grooves 26 forreceiving V belts in the usual manner. The upper part of the pulley 24is U-shaped in cross section and includes an upwardly-extending sleeve28 fitting around a bearing sleeve 30 carried on the exterior surface ofthe static-nary sleeve 10. The lower portion of the stationary sleeve 10is provided with a lock ring member of known construction, not shown,for supporting an annular bearing unit on which the pulley 24 issupported and operated.

The means for coupling the driving pulley 24 to the eccentric 14includes a bottom driving disc 32 bolted to the bottom of the pulley 24-by bolts 34. The pulley 24 and driving disc 32 are flanged, as shown,and are secured together in a fluid tight manner by means of the bolts34. The bottom portion of driving disc 32 is provided at its center witha fitting 36 adapted to provide a stufling box and means for supplyinglubricating oil to the interior of the crusher and the bearings referredto above, but all such features have been omitted from the showing inorder to avoid confusion, since they have nothing to do with the presentinvention. The driving disc 32 integrally includes a pair of similarsubstantially semi-annular spaced supports 38 facing each other andarranged in a circular arc concentric with the axis of rotation of thedriving disc 32. The supports 38 extend upwardly from the driving discand have upper machined surfaces in the same horizontal plane. A dogcoupling member so in driving connection with the supports 38 and indriving connection with the lower portion of the eccentric sleeve 14 ismounted on the supports 38 and in turn carries the weight of theeccentric sleeve 14.

The supports 38 are spaced so as to provide slots 42 at 180 with respectto each other serving as keyways to provide a coupling between thedriving disc and the dog coupling member 40, the latter of which isgenerally cupshaped with its upwardly-extending rim 43 cut to provideoppositely-arranged keyways 44 receiving downwardlyextending keyprojections 46 provided on the lower rim of the eccentric sleeve 14. Thecoupling member 40 is generally cylindrical in shape and ofapproximately the same diameter as the lower portion of the eccentricsleeve, and except for the keyways 4 4 and the keys 46, the engagingsurfaces of the lower end of the eccentric sleeve and the upper end ofthe coupling member are horizontal as illustrated.

In accordance with the invention the bottom of the coupling member 40presents a plain flat surface resting on the upper surfaces of thesupports 38, and the engaging surfaces are machined and arranged in ahorizontal plane, or at right angles to the axis of rotation of thedriving disc 32. The coupling member 40 is connected in drivingrelationship with the supports 38, which together form a substantiallycircular structure, by securing dog keys or key blocks 48, locatedrespectively in the slots 42, to the underside of the coupling member asat 180 with respect to each other and at 90 with respect to the keyways44. The dog key blocks 48, according to the invention, are secured tothe bottom of the coupling mem ber 40 by means of shear bolts 50extending through bores in the inwardly-projecting bottom web 51 of thecoupling member and respectively through bores in the dog key blocks 48,as shown in FIGS. 1 and 3 of the drawings.

Each of the shear bolts 50 is mounted in place with upper and lower lockwashers 52 and with nuts 54 drilled and held in position by cotter pins56. The dog key blocks 48 preferably extend the full length and width ofthe slots or keyways 42 in the manner illustrated in FIGS. 1 and 3 ofthe drawings. Each of the shear bolts 50 is preferably a stress relievebolt and provided with a weakening notch at the position of theinterface between the supports 38 and the bottom of the coupling member40. As illustrated in FIGS. 1 and 3, this weakening notch comprises anannular wide oval groove 58 extending completely around the bolt andproviding a shearing posi tion symmetrically located at the interfacereferred to.

The improved safety coupling arrangement supports the weight of theeccentric sleeve from the driving disc 32, which in turn is supported bythe pulley 24 carried by the stationary sleeve and provides a flexibleconnection or coupling between the driving disc and the cocentricsleeve, so that there may be some relative lateral movement between theeccentric sleeve and the coupling member 40 in one direction and betweenthe coupling member 40 and the supports 38 at 90 to said direction.Furthermore, the rotary motion imparted to the driving disc by thepulley 24- is transmitted through the dog key blocks 48 to the couplingmember 40 and from this member by means of the keys or projections 46 tothe eccentric sleeve 14.

In the operation of the gyratory crusher under normal conditions theshear bolts 50 are adequate to carry the normal rotational load appliedto the eccentric sleeve 14, but when an uncrushable object such as apiece of tramp iron, comes between the crushing elements of the crusherand stops the motion of the main shaft 18 and the rotation of theeccentric sleeve 14, the bolts 50 are sheared off at the position of theweakening grooves 58, thereby permitting the continued rotation of thepulley 24 and driving disc 32 without damaging the crusher. The shearbolts for a to ton crusher, for example, are one inch in diameterprovided with an oval groove inch wide and cut to leave from 0.55 to0.65 inch at the shear position.

When the shear bolts 50 are sheared off, the lower portions merely fallinto the bottoms of the slots 42. Thereafter, after removing the trampiron from between the crushing elements of the crusher, the broken shearbolts are readily replaced in a relatively short time by unbolting thedriving disc 32 from the pulley and lowering the driving disc, thecoupling member 40 and the eccentric sleeve sufficiently to permitaccess to the coupling member for replacing the shear bolts. Even with alarge size gyratory crusher, the shear bolts may be replaced in a matterof two hours, which is nothing compared to the losses which would beincurred if parts of the crusher were wrecked.

While the supports 38 have been described as substantiallysemi-cylindrical, except for the slots 42, it is to be understood thatthe support structure may be a cylindrical ring provided with keywayslots in its upper portion corresponding to the slots 42 for receivingthe dog key blocks 48 and the lower ends of the shear bolts 50.Furthermore, while the dog coupling member 40 is illustrated as beingkeyed to the lower rim of the eccentric sleeve, it is to be understoodthat it may be coupled to such rim in any other suitable manner. It isalso to be understood that the safety structure provided by the shearbolts and dog key blocks may be located at the position of the engagingsurfaces of the eccentric sleeve and the coupling member 40, invertingthe coupling member, instead of in the connection between the drivingdisc 32 and the coupling member 48, in which case the coupling member 48would be keyed to the support by means of interlocking keys and keyways.The location of the safety coupling structure in the relationshipillustrated is, however, regarded as more convenient.

What I claim is:

1. In a gyratory crusher including an upright main crusher shaft thelower portion of which is surrounded by an eccentric sleeve for gyratingthe shaft, a driving pulley for rotating the eccentric sleeve, arotatable driving disc fixed to the pulley and supporting the eccentricsleeve in operative position around the lower portion of the shaft, anda drive coupling between the driving disc and the eccentric sleeveincluding a coupling member having a driving connection with theeccentric sleeve and a driving connection with the driving disc, theimprove-- ment comprising spaced dog keys mounted on and secured to thecoupling member and constituting a part of one of said drivingconnections of the coupling member, and a shear bolt securing each ofsaid dog keys to the coupling member, said shear bolts carrying thedriving load from the driving disc to the eccentric sleeve, whereby saidshear bolts are sheared ofi releasing the dog keys from the couplingmember thereby avoiding damage to the crusher when an uncrushable objectcomes between the crushing elements of the crusher.

2. A gyratory crusher as claimed in claim 1, in which the shear boltsare mounted parallel to the axis of rotation of the driving disc andeach includes a weakening notch at the position of the interface betweenthe coupling member and the dog key secured by the shear bolt.

3. In a gyratory crusher including an upright main crusher shaft thelower portion of which is surrounded by an eccentric sleeve for gyratingthe shaft, a driving pulley for rotating the eccentric sleeve, arotatable driving disc fixed to the pulley and supporting the eccentricsleeve in operative position around the lower portion of the shaft, anda flexible drive coupling between the driving disc and the eccentricsleeve including a dog coupling member having a driving connection withthe lower portion of the eccentric sleeve, the improvement comprising anupwardly-extending support attached to the upper portion of the drivingdisc on which the dog coupling member is supported, said support havingoppositely arranged keyway slots adjacent the dog coupling member, a dogkey block in each keyway slot, and a shear bolt securing each of saiddog key blocks to the bottom of the dog coupling member, said shearbolts carrying the driving load from the driving disc to the eccentricsleeve, whereby said shear bolts are sheared off releasing the dog keyblocks from the dog coupling member thereby avoiding damage to thecrusher when an uncrushable object comes between the crushing elementsof the crusher. I

4. A gyratory crusher as claimed in claim 3, in which the dog couplingmember and the support have plain horizontal engaging surfaces and saidshear bolts are each provided with a weakening notch located at theplane of said engaging surfaces.

5. A gyratory crusher as claimed in claim 3, in which the supportattached to the upper portion of the driving disc comprises a pair ofspaced substantially semi-annular members integral with the driving discand located in a circular arc concentric with the axis of. rotation ofthe driving disc and below the lower rim of the eccentric sleeve, saidsemi-annular members .being arranged to present said oppositely arrangedkeyway slots, and said dog coupling member is of cup-shaped form with aplain bottom surface resting on the upper surfaces of said substantiallysemi-annular members.

References Cited in the file of this patent UNITED STATES PATENTS VanSaun Oct. 18, 1927 Brownstein May 9, 1939

